Secure multi-party device pairing using sensor data

ABSTRACT

Content is securely shared between communication devices in an ad-hoc manner by employing common sensing context to establish pairing between the communication devices. In one aspect, the communication devices are within a specified distance from each other and sense common signals from their environment over a specified time period. The common signals are analyzed to determine an initialization or session key, which is utilized to secure content transfer between the communication devices. Additionally or alternatively, the key is utilized to provide access to virtual (e.g., digital content) and/or physical (e.g., buildings) resources.

TECHNICAL FIELD

The subject disclosure relates to wireless communications and, moreparticularly, to secure multi-party device paring using sensor data.

BACKGROUND

Communication devices are seeing an explosive growth in content sharingvia ad-hoc wireless networks. Conventional systems request users toperform multiple manual steps prior to setting up a secure connection(e.g., Bluetooth® connection) between two or more device to share thecontent. For example, the steps can include forming a group, approvingparticipants, entering passwords or pins on each device, etc. Once asecure connection has been established, content can be shared betweentwo previously unassociated devices in an ad-hoc manner, for example,people at a meeting can share documents, people sharing a meal can sharepictures, people at a concert or sporting event can share media files,etc. Other conventional systems utilize Near Field Communication (NFC)to transfer content from one NFC-enabled device to another NFC-enableddevice. NFC is a short-range radio technology that enables communicationbetween the NFC-enabled devices when they are very close to each other(e.g. within a distance of 1.5 cm). Most often, the two NFC-enableddevices physically touch each other (“tap”) to exchange of small amountsof content within the duration of the tap.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate example systems that facilitates multi-deviceparing based on common context data.

FIG. 2 illustrates an example system that facilitates a securecommunication between two (or more) user equipment.

FIG. 3 illustrates an example system that facilitates session keygeneration for pairing a set of user equipment.

FIG. 4 illustrates an example system that facilitates secure contenttransfer among a group of devices.

FIG. 5 illustrates an example system that facilitates secure access ofdata stored in a cloud device.

FIG. 6 illustrates an example system that facilitates authorizing accessto a physical resource based on multi-device pairing.

FIG. 7 illustrates an example system that initializes user equipment tofacilitate group pairing based on common context data.

FIG. 8 illustrates an example system that facilitates automating one ormore features in accordance with the subject embodiments.

FIG. 9 illustrates a non-limiting example scenario that illustratespairing multiple devices based on common context sensing.

FIG. 10 illustrates an example method that facilitates pairing a set ofdevices based on common context data.

FIG. 11 illustrates an example method that facilitates generation of acryptographic key for pairing a group of communication devices.

FIGS. 12A-12B illustrate example methods that facilitate secure contenttransfer between multiple devices.

FIG. 13 illustrates an example block diagram of a user equipmentsuitable for multi-device pairing based on common context sensing.

FIG. 14 illustrates a block diagram of a computer operable to executethe disclosed communication architecture.

FIG. 15 illustrates a schematic block diagram of an exemplary computingenvironment in accordance with the various embodiments.

DETAILED DESCRIPTION

One or more embodiments are now described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the various embodiments. It may be evident,however, that the various embodiments can be practiced without thesespecific details, e.g., without applying to any particular networkedenvironment or standard. In other instances, well-known structures anddevices are shown in block diagram form in order to facilitatedescribing the embodiments in additional detail.

As used in this application, the terms “component,” “module,” “system,”“interface,” “service,” “platform,” or the like are generally intendedto refer to a computer-related entity, either hardware, a combination ofhardware and software, software, or software in execution or an entityrelated to an operational machine with one or more specificfunctionalities. For example, a component may be, but is not limited tobeing, a process running on a processor, a processor, an object, anexecutable, a thread of execution, computer-executable instruction(s), aprogram, and/or a computer. By way of illustration, both an applicationrunning on a controller and the controller can be a component. One ormore components may reside within a process and/or thread of executionand a component may be localized on one computer and/or distributedbetween two or more computers. As another example, an interface caninclude input/output (I/O) components as well as associated processor,application, and/or API components.

Further, the various embodiments can be implemented as a method,apparatus, or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement one or moreaspects of the disclosed subject matter. An article of manufacture canencompass a computer program accessible from any computer-readabledevice or computer-readable storage/communications media. For example,computer readable storage media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips. . . ), optical disks (e.g., compact disk (CD), digital versatile disk(DVD) . . . ), smart cards, and flash memory devices (e.g., card, stick,key drive . . . ). Of course, those skilled in the art will recognizemany modifications can be made to this configuration without departingfrom the scope or spirit of the various embodiments.

In addition, the words “example” or “exemplary” is used herein to meanserving as an example, instance, or illustration. Any aspect or designdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects or designs. Rather, use ofthe word exemplary is intended to present concepts in a concretefashion. As used in this application, the term “or” is intended to meanan inclusive “or” rather than an exclusive “or.” That is, unlessspecified otherwise, or clear from context, “X employs A or B” isintended to mean any of the natural inclusive permutations. That is, ifX employs A; X employs B; or X employs both A and B, then “X employs Aor B” is satisfied under any of the foregoing instances. In addition,the articles “a” and “an” as used in this application and the appendedclaims should generally be construed to mean “one or more” unlessspecified otherwise or clear from context to be directed to a singularform.

Moreover, terms like “user equipment,” “communication device,” “mobiledevice,” and similar terminology, refer to a wired or wireless deviceutilized by a subscriber or user of a wired or wireless communicationservice to receive or convey data, control, voice, video, sound, gaming,or substantially any data-stream or signaling-stream. The foregoingterms are utilized interchangeably in the subject specification andrelated drawings. Data and signaling streams can be packetized orframe-based flows. Aspects or features of the disclosed subject mattercan be exploited in substantially any wired or wireless communicationtechnology; e.g., Universal Mobile Telecommunications System (UMTS),Wi-Fi, Worldwide Interoperability for Microwave Access (WiMAX), GeneralPacket Radio Service (GPRS), Enhanced GPRS, Third Generation PartnershipProject (3GPP) Long Term Evolution (LTE), Third Generation PartnershipProject 2 (3GPP2) Ultra Mobile Broadband (UMB), High Speed Packet Access(HSPA), Zigbee, or another IEEE 802.XX technology. Additionally,substantially all aspects of the disclosed subject matter can beexploited in legacy (e.g., wireline) telecommunication technologies.

Furthermore, the terms “user,” “subscriber,” “consumer,” and the likeare employed interchangeably throughout the subject specification,unless context warrants particular distinction(s) among the terms. Itshould be appreciated that such terms can refer to human entities orautomated components supported through artificial intelligence (e.g., acapacity to make inference based on complex mathematical formalisms),which can provide simulated vision, sound recognition and so forth.

The systems and methods disclosed herein facilitate content sharingbetween devices in an ad-hoc manner based on common sensing context toestablish pairing between devices. In one aspect, parameters associatedwith the common sensing context can be synchronized between the devices.For example, the parameters can define when to start the sensing, whento stop the sensing, how to collect the context data, which sensors touser, which features to extract from the sensed data, etc. The devicescan utilize the sensed context data to generate a key that can beemployed to securely transfer data between the devices and/or toauthorize the devices to access a device, data storage, and/or physicallocation.

Referring initially to FIG. 1A, there illustrated is an example system100 that facilitates multi-device paring based on common context data,according to one or more aspects of the disclosed subject matter. System100 can facilitate key generation based on common context data andutilize the key to secure communications between the devices. Userequipment (UE) (102 a, 102 b) can include most any electroniccommunication device such as, but not limited to, most any consumerelectronic device, for example, a tablet computer, a digital mediaplayer, a digital photo frame, a digital camera, a cellular phone, apersonal computer, a personal digital assistant (PDA), a smart phone, alaptop, a gaming system, etc. Further, UEs (102 a, 102 b) can alsoinclude, LTE-based devices, such as, but not limited to, most any homeor commercial appliance that includes an LTE radio. It can be noted thatUEs (102 a, 102 b) can be mobile, have limited mobility and/or bestationary.

In one embodiment, UEs (102 a, 102 b) can be located close to each other(e.g., within a predefined distance) such that they can simultaneously(and/or almost simultaneously) sense context data 108 from their commonsurroundings via sensors (104 a, 104 b). Moreover, the sensors (104 a,104 b) can include an accelerometer, a gyroscope, a camera, amicrophone, a light sensor, a humidity sensor, a temperature sensor, alocation sensor (e.g., Global positioning system), and the like. Thecommon context data 108 can include, but is not limited to, a continuoussignal (e.g., that can change over time) that can be sensed for apredefined and/or dynamically defined period of time. For example, thecontinuous signal can be an audio signal, a video signal, a commonmotion experienced by both UEs (102 a, 102 b), a sequence of vibrations,etc. Additionally or alternatively, the sensors (104 a, 104 b) canmeasure static content data, such as, but not limited to, an imagecaptured by a camera.

According to an aspect, the UEs (102 a, 102 b) include key generationcomponent (106 a, 106 b) that analyze data collected by one or moresensors to determine a session key that can be utilized toencrypt/decrypt communication data transmitted between the UEs (102 a,102 b). Since both the sensors (104 a, 104 b) sense the same (orsubstantially the same) common context data 108, the key generated bythe respective key generation components (106 a, 106 b) can beidentical. In one example, the key generation components (106 a, 106 b)can employ one or more techniques to compensate for variations in commoncontext data 108 measured by the sensors (104 a, 104 b), for example,due to hardware capabilities and/or restrictions of the sensors (104 a,104 b), a variation in a distance of the UEs (102 a, 102 b) from asignal source, etc. For example, if the UE 102 a is placed at a locationthat is slightly further from a signal source, than the location atwhich UE 102 b is placed, the sensor 104 a can receive the signal fromthe signal source after the signal is received at sensor 104 b. However,the key generation components (106 a, 106 b) can analyze the datacollected by the respective sensors (104 a, 104 b) to extract featuresthat are independent of these variations, such as, but not limited to,determining a pattern or sequence in the signal. In another example, dueto different sensitivity (e.g., different sensor implementations,protective cases, etc.), the signal amplitude as observed by the UEs(102 a, 102 b) can vary. As noted above, to compensate for suchvariations, the key generation components (106 a, 106 b) can employpatterns/sequences observed in the received signal data to generate thesession key. In one aspect, the signal data collected by the respectivesensors (104 a, 104 b) can also be filtered and/or smoothed, prior togeneration of the session key (e.g., based on machine learninganalysis).

Typically, a multi-sensing modality approach for session key derivationis much more robust than any single technique in isolation since itprovides a more robust confidence about the commonality of the context.According to one aspect, location data (e.g., current location and/orarea within which the devices to be paired are located) and/or timestampdata (e.g., current time and/or time period during which the sensorscollect the common context data) can also be utilized to improveconfidence about the commonality of the context.

FIG. 1B illustrates a system 150 that depicts a group-wise pairing ofmore than two UEs based on the common context data 108. In one aspect,system 150 can be utilized to pair most any number of UEs (102 a-102 x;wherein “x” can be an integer greater than (or equal to) 2). In thisexample scenario, the group-wise pairing is facilitated in parallel. Forexample, the UEs (102 a-102 x) can simultaneously (or almostsimultaneously) sense (e.g., via respective sensors 104 a-104 x) thecommon context data to facilitate a generation of identical/matchingcryptographic keys (e.g., via respective key generation components 106a-106 x). In general, the group-wise pairing based on the group ofdevices simultaneously (or almost simultaneously) sensing common contextdata 108 to generate cryptographic keys in parallel, is faster and lesstedious than performing sequential pair-wise pairings (between twodevices at a time). In addition, repeating and/or replicating identicalsignals (at different times), for example, vibrations, live(non-recorded) audio/video streams, or non-recorded image data,temperature signals, humidity signals, etc. found in an environmentsurrounding the group of devices and/or most any signals that wouldchange over time is extremely challenging; thus, making it almostimpossible to obtain identical keys if sequential pair-wise pairing isestablished between two devices at a time. For example, duringsequential pair-wise pairings for a group of more than two devices,Device#1 and Device#2 would be paired at a first time, then Device#1 andDevice#3 would be paired at a second time, after which Device#1 andDevice#4 would be paired at a third time, and so on and so forth. Sincethe common context data typically changes with time, obtaining identicalkeys at the different devices during sequential pair-wise paring ischallenging. In contrast, system 150 employs a faster and easier grouppairing technique that enables multiple devices (e.g., UEs (102 a-102x)) to sense common context data 108 concurrently (or almostconcurrently) and generate identical session keys in parallel. Forexample, the UEs (102 a-102 x) can be placed on a common surface (e.g.,a table) and the common context data 108 can comprise a sequence ofknocks applied to the table. In this example scenario, sensors (104a-104 x) can simultaneously (or substantially simultaneously) sensevibrations due to the knocks to determine a unique pattern/sequence thatcan be employed by the key generation components (106 a-106 x) todetermine matching/identical keys for pairing the UEs (102 a-102 x). Thekeys can be utilized to facilitate secure communications between the UEs(102 a-102 x).

Referring now to FIG. 2, there illustrated is an example system 200 thatfacilitates a secure communication between two (or more) UEs, inaccordance with an aspect of the subject disclosure. In one aspect,system 200 facilitates secure pairing of UEs (102 a, 102 b) based on theUEs (102 a, 102 b) sensing one or more common signals from theirenvironment and utilizing the common signal to determine aninitialization or session key. Subsequent to the pairing, the UEs (102a, 102 b) can share content in a secure manner (e.g., impede anunauthorized device from accessing/decrypting the shared content). Forexample, the UEs (102 a, 102 b) can share documents, photos, mediafiles, etc. stored in a local or remotely accessible memory (not shown).The term “pairing” as used herein refers to establishing a securecoupling/connection between two or more devices by generating a commonsecret such as (but not limited to) a cryptographic key. If identicalkeys are generated and/or stored by the devices, they are considered tobe paired or bonded. It is noted that the UEs (102 a, 102 b), sensors(104 a, 104 b), and key generation components (106 a, 106 b) can includefunctionality as more fully described herein, for example, as describedabove with regard to systems 100 and 150. Further, it is noted thatalthough only two UEs (102 a, 102 b) are depicted in FIG. 2, most anynumber of UEs can be utilized by system 200 to facilitate group-wisepairing (as described above with respect to system 150).

In one embodiment, during the pairing, sensors (104 a, 104 b) collectsignal data (e.g., for a predefined and/or dynamically determined timeperiod, sample periodically, etc.) from a common environment surroundingboth the UEs (102 a, 102 b). According to an aspect, the synchronizationcomponents (202 a, 202 b) ensure that the signal data collected by thesensors (104 a, 104 b) is identical or approximately the same. Forcontinuous signals, a time period for which the signal data is to becollected can be specified by the respective synchronization components(202 a, 202 b). In one example, the synchronization components (202 a,202 b) can determine data collection parameters, such as (but notlimited to) a time period (e.g., predefined and/or dynamicallydetermined time period), a sampling frequency, information defining aset of the sensors (104 a, 104 b), which are to be utilized to measurethe signal data, a time at which the measurement is to bestarted/stopped, etc. In another example, the synchronization component202 a can simply broadcast a signal that instructs sensors 104 b of UE102 b to start/stop sensing signal data (and/or vice versa).

In one example, the data collection parameters can be manually enteredby a user of the UE (e.g., UE 102 a) that initiates the pairing/contenttransfer. In another example, the data collection parameters can bepredefined by a manufacturer(s) of the UEs (102 a, 102 b) and/or aservice provider (e.g., mobility network operator). Additionally oroptionally, the UEs (102 a, 102 b) can exchange data collectionparameters prior to the content transfer, for example, via acommunication network, such as, a WiFi network, a cellular network, aZigBee network, and the like. For example, if determined that content isto be transferred from UE 102 a to UE 102 b, the synchronizationcomponent 202 a can provide data collection parameters to thesynchronization component 202 b (and vice versa). According to anaspect, the synchronization components (202 a, 202 b) can perform adynamic negotiation process, wherein a least common capability/sensingmodality of the devices to be paired (e.g., UE 102 a, 102 b) can bedetermined and utilized for content sensing and/or key generation.

The key generation components (106 a, 106 b) can analyze the signal dataand determine a session key using at least a portion of the signal data.Since the signal data collected by the sensors (104 a, 104 b) is thesame (or almost the same), the key generation components (106 a, 106 b)can generate identical/matching keys. In one example,features/properties of the signal data can be extracted and employed togenerate the session key. Additionally or optionally, prior to, orconcurrent with, the transfer of content, the UEs (102 a, 102 b) canemploy most any key synchronization technique to verify and/or ensurethat the key generation components (106 a, 106 b) have generated thesame session key.

In one aspect, content transfer components (204 a, 204 b) can utilizethe key to encrypt/decrypt content (e.g., multimedia files, documents,etc.) exchanged between the UEs (102 a, 102 b). For example, contenttransfer component 204 a can encrypt content that is to be transferredfrom UE 102 a to UE 102 b, for example, by employing most any encryptionalgorithm (e.g., hash functions, Rivest-Shamir-Adleman (RSA) algorithm,advanced encryption standard (AES), etc.). Further, the content transfercomponent 204 a can transmit and/or broadcast the encrypted data via apublic (or private) communication network (e.g., WiFi, cellular network,Zigbee, Near Field Communication (NFC), etc.) In this example scenario,the content transfer component 204 b can receive the encrypted contentand can utilize the session key generated by the key generationcomponent 106 b to decrypt the encrypted content, for example, byemploying a decryption algorithm corresponding to the encryptionalgorithm utilized by the content transfer component 204 a.

Referring now to FIG. 3, there illustrated is an example system 300 thatfacilitates session key generation for pairing a set of UEs, accordingto an aspect of the subject disclosure. Typically, system 300 can beimplemented by a UE, for example, UE 102 a and/or UE 102 b. It is notedthat the sensor(s) 104 can be substantially similar to sensor(s) 104 aand/or sensor(s) 104 b and can include functionality as more fullydescribed herein, for example, as described above with regard tosensor(s) 104 a and/or 104 b. Further, the key generation component 106can be substantially similar to key generation component 106 a and/orkey generation component 106 b and can include functionality as morefully described herein, for example, as described above with regard tothe key generation components 106 a and/or 106 b.

In one aspect, sensor(s) 104 can include (but are not limited to) anaccelerometer 302 ₁ (e.g., to measure vibration signals, and/or speed,direction, acceleration, and/or velocity of the UE), a gyroscope 302 ₂(e.g., to measure vibration signals and/or orientation of the UE), alocation sensor 302 ₃ (e.g., a GPS system to determine a geographicallocation of the UE), a microphone 302 ₄ (e.g., to measure audiosignals), an optical sensor 302 ₅ (e.g., to measure ambient light), acamera 302 ₆ (e.g., to record images or a video signals), a temperaturesensor 302 ₇ (e.g., to measure ambient temperature), and/or a humiditysensor 302 ₈ (e.g., to measure ambient humidity). It can be appreciatedthat most any sensor and/or combination of sensors(s) can be employed tomeasure context data common to the UEs that are to be paired.

As discussed supra, the sensors(s) 104 can be controlled based oninstructions received from a synchronization component (e.g., 202 a, 202b). For example, sensors(s) 104 can start and/or stop sensing signaldata based on predefined times and/or dynamically in response todetection of an event (e.g., sensing a predefined start/stop sequence).According to an aspect, a fusion component 304 can combine the signaldata collected by the sensor(s) 104 to generate a seed (e.g., a sequenceof bits). As an example, the fusion component 304 can comprise asequence generator that employs most any concatenation and/oraggregation technique to generate a sequence of bits. Moreover, whenmultiple sensors are utilized, the fusion component 304 can aggregateand/or combine sequences determined from respective signals sensed bythe multiple sensors to generate the seed. For example, the fusioncomponent 304 can employ a logical function, such as, but not limitedto, an exclusive OR (XOR) function, and/or more complex fusionalgorithms to combine sequences determined from different sensor inputs.

In one aspect, the fusion component 304 can extract key properties fromthe signal data to facilitate generation of the seed. For example, incase of an audio signal recorded by microphone 302 ₄, the fusioncomponent 304 can determine a sequence based on an absence or presenceof speech and determine the seed based on the sequence. As anotherexample, in case an image is captured by cameras 302 ₆, the fusioncomponent 304 can determine the seed based on basic and/or inherentproperties of the image such as (but not limited to) a size, an aspectratio, number of colors used, pixel color distribution across the image,etc., and/or based on derived properties, which are invariant withrespect to picture rotation, lighting, transformation etc. and can bedetermined (e.g., by the fusion component 304) based on Eigenvalue-basedfeatures, Scale-invariant feature transform (SIFT) descriptors, Harrisdescriptors, Multi-scale Oriented Patches (MOPS) descriptors, and thelike. According to an aspect, the fusion component 304 can recognizefeatures within an image and/or classify an image based on most anycomputer vision technique/algorithm and determine a sequence based onthe features and/or classification data.

In general, the generation of the seed based on extracted propertiesfrom the signal data can also remedy the discrepancies/variationsobserved in signal data collected by different sensors of different UEs.As an example, the discrepancies/variations can be introduced due todifferences in hardware capabilities (e.g., differing cameraresolutions) and/or differences in position/location (e.g., distance ofa sensor from a signal source). In one aspect, the fusion component 304can select features that are to be extracted from the signal data basedon a least common sensing modality supported by all the devices that arebeing paired. For example, the lowest camera resolution supported by allthe devices can be considered during extraction of features from a videosignal. Accordingly, if one of the devices has a very low cameraresolution, the fusion component 304 can determine a sequence based onchanges in brightness (e.g., bright vs. dark) rather than details withinthe image that would not be accurately captured by the low-resolutioncamera.

In an aspect, the key generation component 106 can employ the seed togenerate a cryptographic key (e.g., a session key and/or aninitialization key) that is employed to facilitate secure contenttransfer and/or authorize access to restricted locations (e.g., virtualand/or physical locations). As an example, the cryptographic key caninclude most any opaque and/or unique (for a specific time and/orsession), number or code that can be valid for a time period that ispredefined (e.g., by a user, service provider, device manufacturer,etc.) and/or dynamically defined based on an event/criterion, such as(but not limited to) expiration of a timer, termination of a datasession, etc. In one aspect, the key generation component 106 cangenerate the cryptographic key by employing most any number generatorthat can create the cryptographic key based on the seed determined bythe fusion component 304. For example, the key generation component 106can utilize an MD5 hash of the seed to facilitate key generation. inanother aspect, the seed itself can be utilized as the cryptographickey.

In one example, the cryptographic key can be symmetric (e.g., the samekey can be utilized for both encryption and decryption of content). Inanother example, the cryptographic key can be utilized as a private keyand utilized in combination with a public key. Typically, in thisexample scenario, the cryptographic key can be transmitted (e.g., by thecontent transfer component 204 a, 204 b) along with each message and canbe encrypted with the recipient's public key. According to an aspect,the key generation component 106 can store (e.g., temporarily orpermanently) the cryptographic key within key data store 306. As anexample, the key can be stored in the key data store 306 for the timethat the key is valid (e.g., during a session, for a predefined time,and/or until a timer expires or a data session is terminated, until theuser explicitly instructs the UE to delete the key, etc.).

Further, it is noted that the key data store 306 can include volatilememory(s) or nonvolatile memory(s), or can include both volatile andnonvolatile memory(s). Examples of suitable types of volatile andnon-volatile memory are described below with reference to FIG. 15. Thememory (e.g., data stores, databases) of the subject systems and methodsis intended to comprise, without being limited to, these and any othersuitable types of memory.

FIG. 4 illustrates an example system 400 that facilitates secure contenttransfer among a group of devices according to an aspect of thedisclosed subject matter. Typically, system 400 can facilitategroup-wise pairing of the devices (102 a-1020 based on context data thatcan be simultaneously (or almost simultaneously) sensed by the devices.The UE 102 a, UE 102 b, and the content transfer component 204 a caninclude functionality as more fully described herein, for example, asdescribed above with regard to systems 100-300. Further, the UEs 102c-102 f can be substantially similar to UEs 102 a and/or 102 b and caninclude functionality as more fully described herein, for example, asdescribed above with regard to the UEs 102 a and/or 102 b. Although FIG.4 illustrates a group of six UEs (102 a-102 f), the subject system isnot that limited and most any number (e.g., two or more) of UEs can beincluded within the group. As discussed above, since all the UEs (102a-102 f) sense common context data, respective key generation components(e.g., 106 a, 106 b) of the UEs (102 a-102 f) can generate (e.g., inparallel) identical cryptographic keys (e.g., 402 a).

In one aspect, the content transfer component 204 a can employ the key402 a to secure communication among the UEs (102 a-102 f). Moreover, thecontent transfer component 204 a can include an encryption component 404a that can employ most any encryption algorithm (e.g., hash functions,RSA algorithm, AES, etc.) to encrypt content (e.g., documents, files,photos, videos, music, etc.) received from the content data store 406 ausing the key 402 a. In one example, the content transfer component 204a can broadcast the encrypted content via a communication network 412(e.g., WiFi, cellular, ZigBee, NFC, etc.) and only the paired UEs (102b-102 f) will be able to decrypt the content. Other devices (not shown)that can be coupled to the communication network 412 but have not beenpaired with UEs (102 a-102 f) may be able to access the broadcastedcontent but will not be able to decrypt the content. Accordingly,content transfer can be restricted to authorized devices, for example,UEs (102 b-1020 that have been paired.

In another aspect, content broadcasted by one or more of the UEs (102b-1020 can be received by the content transfer component 204 a anddecrypted using the decryption component 408 a. As an example, tofacilitate decryption of the broadcasted content, the decryptioncomponent 408 a can utilize a decryption algorithm corresponding to theencryption algorithm employed by the one or more of the UEs (102 b-1020.The key 402 a (or another key derived from key 402 a) can be employed bythe decryption algorithm. In one example, the key 402 a can be symmetric(e.g., the same key can be utilized for both encryption and decryptionof content). In another example, the key 402 a can be utilized as aprivate key and utilized in combination with a public key associatedwith a recipient and/or sender. Further, the decryption component 408 acan store the decrypted content in the content data store 406 a.Additionally or optionally, the decryption component 408 a can instructan output interface (e.g., display screen, microphone, etc.) to presentthe received content to the user. In one aspect, the key 402 a can beutilized for encryption/decryption (e.g., by the encryption component414 a/decryption component 408 a) until the key 402 a is determined tobe valid (e.g., during a communication session, for a predefined time,and/or until a timer expires or a data session is terminated, untildeleted by the user, etc.).

Additionally or optionally, prior to, or concurrent with, the transferof content, a verification component 410 a can be utilized to confirmand/or ensure that the respective key generation components of the UEs(102 a-1020 have generated the same/identical/matching key. In oneexample, the verification component 410 a can perform a keysynchronization protocol between the UEs (102 a-102 f) by instructingthe encryption component 404 a to encrypt sample/test data by utilizingcandidate keys that are generated by employing different subsets of abit sequence/seed generated by the fusion component 304. Additionally oralternatively, the verification component 410 a can instruct the UEs(102 a-102 f) to exchange data with checksum values encrypted using thecandidate keys. In yet another example scenario, wherein UEs (102 a-102f) generate public and private keys, the UEs (102 a-102 f) canfacilitate key synchronization by comparing the respective public keysthat have been generated by the UEs (102 a-102 f). For example, the UEs(102 a-102 f) can broadcast their public keys and if the public keysmatch it can be determined that same/identical/matching private keyshave been generated. Once the verification component 410 a selects a keyfrom the candidate keys and/or confirms that the UEs (102 a-1020 havegenerated the same/identical/matching key, the content transfercomponent 204 a can initiate and perform a secure content transfer amongthe UEs (102 a-1020 by employing the key.

Referring now to FIG. 5, there illustrated is an example system 500 thatfacilitates secure access of data stored in a cloud device (e.g., devicewithin a private network), according to one or more aspects of thedisclosed subject matter. System 500 can facilitate content sharingbetween two or more UEs (e.g., UE 102 a and UE 102 b). UE 102 a and UE102 b can be substantially similar and can include functionality as morefully described herein, for example, as described above with regard tosystems 100-400.

In one aspect, UE 102 a and UE 102 b can sense and/or record (e.g., viasensor(s) 104 a and 104 b) common context data to facilitate pairing. Aspart of the pairing, the UE 102 a and UE 102 b can generate (e.g., viakey generation components 106 a and 106 b) identical cryptographic keysbased on the common context data. In one example scenario, UE 102 a cansecurely share data with UE 102 b, by encrypting the data using the keyand transferring the data to a shared storage device, for example, acloud device 502 (e.g., of a private or public network). Moreover, theUE 102 a can transfer the encrypted data via most any communicationnetwork and/or utilizing most any communication protocol. Further, theUE 102 b can access and/or receive the encrypted data from the clouddevice 502 and utilize the key to decrypt the data. The decrypted datacan be stored within the UE 102 b and/or displayed on a screen of the UE102 b. In one aspect, the address and/or location (e.g., Universalresource location (URL)) of the cloud device 502 can be known to bothUEs (102 a, 102 b), for example, predefined by a device manufacturer,service provider, etc., and/or determined/defined by the UEs (102 a, 102b) during a synchronization session (e.g., during, as part of, and/orsubsequent to the pairing). It can be appreciated that although theabove example describes transferring data from UE 102 a to UE 102 b, thesubject specification is not so limited and that UE 102 b can alsosecurely transfer data to UE 102 a (and/or multiple paired devices) viathe cloud device 502.

In another example scenario, the keys generated during UE pairing can beutilized to provide access to resources on the cloud device 502. Forexample, UE 102 a can transfer the key to the cloud device 502 (e.g.,cloud server) and instruct the cloud device 502 to share specificresources (e.g., content, processing resources, etc.) with paireddevices (e.g., UE 102 b). Additionally and/or optionally, the UE 102 acan specify access parameters/restrictions (e.g., access time)associated with the access. Moreover, UE 102 b can employ the key toaccess the authorized resources of cloud device 502. In one aspect, thecloud device can perform authentication (e.g., based on the key receivedfrom the UE 102 b) prior to granting the access. As an example, thecloud device 502 can implement various access policies (e.g., predefinedby UE 102 a) to restrict type of access (e.g., read only, read andwrite, temporary access permanent access, etc.) by the UE 102 b. It canbe appreciated that although only two UEs are depicted, system 500 canfacilitate sharing of content between multiple paired devices via acloud device 502.

Referring now to FIG. 6, there illustrated is an example system 600 thatfacilitates authorizing access to a physical resource based onmulti-device pairing, in accordance with an aspect of the subjectdisclosure. To impede unauthorized access, system 600 facilitatesutilization of keys, generated by two or more devices (e.g., UEs 102 a,102 b) based on sensing common context data, to restrict access to aphysical resource (e.g., a room, building, vault, etc.). It can be notedthat UE 102 a and UE 102 b can be substantially similar and can includefunctionality as more fully described herein, for example, as describedabove with regard to systems 100-500.

According to an aspect, UE 102 a and UE 102 b can sense and/or record(e.g., via sensor(s) 104 a and 104 b) common context data to facilitatepairing. As part of the pairing, the UE 102 a and UE 102 b can generate(e.g., via key generation components 106 a and 106 b) identicalcryptographic keys based on the common context data. In one aspect, UE102 a can authorize UE 102 b to access a physical resource, such as, butnot limited to, a house, a room, an area, a vehicle, a vault, etc. basedon the cryptographic keys. As an example, the UE 102 a can transfer thekey to an access control component 602 that controls access to thephysical resource (e.g., via an electronic lock). For example, theaccess control component 602 can be part of a home security system thatrestricts access to a house. Additionally or optionally, the UE 102 acan also provide the access control component 602 with accessparameters, including (but not limited to) timing data that specifies atime interval during which the UE 102 b is authorized to access thephysical resource. Moreover, the UE 102 a can transfer the key via mostany wired or wireless communication network 606 (e.g., a WiFi network, acellular network, etc.). Further, the UE 102 b can communicate with theaccess control component 602 to request for access to the physicalresource. In one aspect, UE 102 b can communicate with the accesscontrol component 602 via a different communication network 608 and/orthe same communication network 606. Moreover, UE 102 b can provide theaccess control component 602 with the key and the access controlcomponent 602 can perform authorization/authentication based on receivedkey. Since the key provided by UE 102 b matches the key provided by UE102 a, the access control component 602 can allow the UE 102 b to accessthe physical resource 604 (e.g., unlock the electronic lock).

In an example scenario, two (or more) friends meeting at a coffee shopcan employ system 600 to pair their respective UEs (e.g., UEs 102 a, 102b) based on sensing common context data in theirenvironment/surroundings. The UEs (e.g., UEs 102 a, 102 b) can generateidentical keys that the first friend can transmit to his home securitysystem (e.g., via UE 102 a). In this example scenario, when the secondfriend arrives at the home, he can use his UE (e.g., UE 102 b) totransmit the key to the home security system, which can employ the keyto authorize the friend and open the house door. This eliminates theneed (and mitigates a security risk) for a homeowner to type the key onthe guests phone. In one aspect, the home security system can remove thekey from its data store after the friend's visit is over (versus using afixed key or physical key shared by all persons accessing the home). Inanother example, system 600 can also be employed to generate and share akey to a hotel room between one or more guests sharing the room. It canbe appreciated that although only two UEs are depicted, system 600 canfacilitate enabling multiple paired devices to access a physicalresource 604.

Referring now to FIG. 7, there illustrated is an example system 700 thatinitializes UEs to facilitate group pairing based on common contextdata, in one aspect of the subject disclosure. It is noted that the UE102 can be substantially similar to UEs 102 a and 102 b, and can includefunctionality as more fully described herein, for example, as describedabove with regard to UEs 102 a and 102 b. Further, synchronizationcomponent 202 can be substantially similar to synchronization components202 a and 202 b, and can include functionality as more fully describedherein, for example, as described above with regard to synchronizationcomponents 202 a and 202 b. Furthermore, the key generation component106 can be substantially similar to key generation component 106 aand/or key generation component 106 b and can include functionality asmore fully described herein, for example, as described above with regardto the key generation components 106 a and/or 106 b.

In one embodiment, the UE 102 can comprise an initialization component702 that can receive, and/or store within initialization data store 704,initialization data that can be utilized during pairing the UE 102 withone or more other UEs based on sensing common context data. In anaspect, the initialization data can be received (e.g., during power-on,during idle mode, periodically, on demand, in response to an event,etc.) from various entities. For example, the initialization data can bespecified by a user via an input interface (e.g., keypad, touch screen,microphone, etc.) of the UE 102. In another example, the initializationdata can be pre-programmed by a manufacturer during devicemanufacturing. In yet another example, the initialization data can beprovided via over-the-air communications (e.g., transmitted by a networkoperator, service provider, etc.). In this example, the initializationcomponent 702 can receive the initialization data from an OTA server 706via most any communication network 708. In one aspect, theinitialization data can be received via an out-of-bands communication.In still another example, the initialization data can be downloaded froman application (app) server (not shown) as part of an update to adevice-pairing app installed on the UE 102.

According to an aspect, the initialization data can include, but is notlimited to, user/manufacturer/service provider preferences and/orpolicies, and/or most any data that can be employed to facilitatepairing two or more devices. As an example, the initialization data caninclude data collection parameters utilized by the synchronizationcomponent 202, such as (but not limited to) a time period for which datais to be sensed, a sampling frequency, information defining whichsensors are to be utilized to measure the signal data (e.g., use onlyvideo data, use audio and temperature data, etc.), a time at which themeasurement is to be started/stopped, a predefined signal (e.g.,pattern/sequence or knocks, a predefined image, a predefined audio tone,etc.) at which the measurement is to be started/stopped, etc. In anotherexample, the initialization data can include parameters utilized by thekey generation component 106, such as (but not limited to) an algorithmor modifications to the algorithm utilized to generate the key, a timeperiod for which the key is to be valid, a policy for expiration ofvalidity of the key, etc. Additionally or alternatively, initializationdata can include an address of shared storage device (e.g., cloud device502), access policies associated with accessing, transferring, and/orsharing content, data transfer preferences (e.g., which communicationnetwork to utilize), etc.

Referring now to FIG. 8, there illustrated is an example system 800 thatemploys an artificial intelligence (AI) component 802, which facilitatesautomating one or more features in accordance with the subjectembodiments. It can be appreciated that the key generation component106, the synchronization component 202, the content transfer component204, the fusion component 304, and the initialization component 702 caninclude respective functionality, as more fully described herein, forexample, with regard to systems 100-700.

An example embodiment, system 800 (e.g., in connection withautomatically determining data collection parameters, keys, and/or datatransfer parameters) can employ various AI-based schemes for carryingout various aspects thereof. For example, a process for determiningoptimal data collection parameters, smoothing/filtering sensor inputdata, determining how to fuse data collected from the various sensors,determining which features of sensed data are to be utilized forsequence generation, determining content sharing, delivery, and/oraccess rights, etc., can be facilitated via an automatic classifiersystem and process. A classifier can be a function that maps an inputattribute vector, x=(x1, x2, x3, x4, xn), to a confidence that the inputbelongs to a class, that is, f(x)=confidence(class). Such classificationcan employ a probabilistic and/or statistical-based analysis (e.g.,factoring into the analysis utilities and costs) to prognose or infer anaction that a user desires to be automatically performed. In the case ofcommunication systems, for example, attributes can be informationreceived from UEs, and the classes can be categories or areas ofinterest (e.g., levels of priorities). A support vector machine (SVM) isan example of a classifier that can be employed. The SVM operates byfinding a hypersurface in the space of possible inputs, which thehypersurface attempts to split the triggering criteria from thenon-triggering events. Intuitively, this makes the classificationcorrect for testing data that is near, but not identical to trainingdata. Other directed and undirected model classification approachesinclude, e.g., naïve Bayes, Bayesian networks, decision trees, neuralnetworks, fuzzy logic models, and probabilistic classification modelsproviding different patterns of independence can be employed.Classification as used herein can also be inclusive of statisticalregression that is utilized to develop models of priority.

As will be readily appreciated from the subject specification, anexample embodiment can employ classifiers that are explicitly trained(e.g., via a generic training data) as well as implicitly trained (e.g.,via observing UE behavior, user/operator preferences, historicalinformation, receiving extrinsic information). For example, SVMs can beconfigured via a learning or training phase within a classifierconstructor and feature selection module. Thus, the classifier(s) can beused to automatically learn and perform a number of functions, includingbut not limited to determining according to a predetermined criteriawhen to start pairing devices, which sensors to utilize, when tostart/stop sensing, features of the sensed signals for generating aseed, how long to store a key in a data store, content that is to betransferred, etc. The criteria can include, but is not limited to,historical patterns, UE behavior, user preferences, service providerpreferences and/or policies, location of the UE, current time, etc.

Referring now to FIG. 9, there illustrated is a non-limiting examplescenario 900 that illustrates pairing multiple devices based on commoncontext sensing, in one aspect of the various embodiments. It is notedthat the UEs 902 ₁-902 _(N) (where N is most any positive integergreater than 1) can be substantially similar to UEs 102 a and/or 102 b,and can include functionality as more fully described herein, forexample, as described above with regard to UEs 102 a and 102 b.Although, FIG. 9 depicts UEs 902 ₁-902 _(N) to be mobile phones, it canbe appreciated that UEs 902 ₁-902 _(N) can be the same or differentdevices (e.g., wired and/or wireless), such as, but not limited to,laptops, tablets, personal computers, gaming modules, etc.

Consider an example scenario wherein the users of UEs 902 ₁-902 _(N)would like to share content among the UEs 902 ₁-902 _(N) in an ad-hocmanner. For example, people at a meeting can share documents (e.g.,meeting agenda, presentation slides, business cards, etc.) and/or peopleat a party, a concert, or sporting event can share multimedia files(e.g., photos, videos, etc.). According to an aspect, systems 100-800can be utilized to set up such sharing and/or content transfer.Moreover, systems 100-800 provide a faster, more efficient, andautomated technique to share the content (e.g., reducing multiple manualinstructions from the users, such as, forming a group, approvingparticipants, entering passwords or pins, etc.). To initiate thepairing, the users can place their UEs 902 ₁-902 _(N) close to eachother (e.g., within a predefined distance such that the UEs canobserve/sense the same (or almost the same) data), for example, on table904. In one aspect, a random pattern of knocks can be applied to thetable at 906. The UEs 902 ₁-902 _(N) can sense (e.g., via respectiveaccelerometers 302 ₁ and/or gyroscopes 302 ₂) the sequence of knocksand/or the pauses between the knocks. In this example, even though theUEs 902 ₁-902 _(N) can receive the sequence slightly at different times(e.g., based on unequal distance from the source), the UEs 902 ₁-902_(N) can still observe the same (or substantially similar) sequence withthe same (or substantially similar) inter-knock delays. In addition, dueto different sensor sensitivities (e.g., different sensorimplementations, protective cases), the signal amplitude as seen by thedifferent UEs 902 ₁-902 _(N) can vary but the UEs can extract commonfeatures (e.g., patterns and/or sequence) from the signals to compensatefor the variations in sensitivity. Machine learning analysis (e.g., bythe respective AI components 802 of the UEs 902 ₁-902 _(N)) can beapplied to the signal in the time and frequency domain to facilitatefiltering and/or smoothing of the signal, and reduce noise. Additionallyor alternatively, the UEs 902 ₁-902 _(N) can also record signals viaother sensors (e.g., sensors 104) and/or utilize timestamp data/and/orlocation data to improve the likelihood of generating identical keysthat are difficult to replicate by unauthorized devices. For example,the UEs 902 ₁-902 _(N) can capture photo snapshots with their cameras.Since they are all on the same table 904, they can capture the samedetails on photos taken at the same time (e.g., a ceiling lamp). Inanother example, the UEs 902 ₁-902 _(N) can analyze a voice commandcaptured at the same time by all the devices.

According to an aspect, the UEs 902 ₁-902 _(N) utilize the common signalfor generating a cryptographic key (e.g., by employing respective fusioncomponents 304 and/or key generating components 106). To ensure that allthe UEs 902 ₁-902 _(N) are recording the same signal (e.g., vibrationfrom knocks) at the same time (or substantially same time), the UEs 902₁-902 _(N) can be synchronized to start and end sensing and/or recordingthe signal at the same time (or substantially same time). In oneexample, a predefined signal (e.g., a double knock on the table surface904, a speech signal of a person saying “start,” etc.) and/or a longenough “silence” (e.g., lack of signal) can be utilized to instruct theUEs 902 ₁-902 _(N) to be ready to record when a subsequent signal (e.g.,vibration) is received. According to an aspect, the UEs 902 ₁-902 _(N)can indicate a readiness to receive signal by displaying certain data,such as, but not limited to, a symbol or a color on their screens (or abeep via their speakers). For example, the UEs 902 ₁-902 _(N) candisplay a green color on their respective screens when they are ready toreceive the signal. Additionally or optionally, a synchronizationprotocol can be executed by the UEs 902 ₁-902 _(N), wherein a designatedUE can broadcast a signal to start/stop sensing the context. In theabove example, once all the UEs 902 ₁-902 _(N) display a green color ontheir screens, the user can apply the random pattern of knocks to thetable at 906.

In one aspect, the UEs 902 ₁-902 _(N) can extract specific properties ofthe signal (e.g., sequence of knocks) to generate a seed (e.g., asequence of bits) that can be employed (e.g., by the respective keygeneration components 106) to determine a session key or initializationkey. Since the seed is based on the common sensing context, a device(not shown) in a different context will not be able to construct thesame seed and thus, will be unable to obtain the same key. For example,a different device (not shown) that is not on the table surface 904 willnot be able to sense the vibrations from the knocks and thus, will notbe able to generate the same key. Accordingly, the different device willbe prevented from decrypting the shared content.

In one aspect, the UEs 902 ₁-902 _(N) can perform (e.g., by employrespective verification components 410 a) a key synchronization protocolto verify that all the devices generated the same key. Once verifiedthat all the UEs 902 ₁-902 _(N) have generated identical keys, the UEs902 ₁-902 _(N) can securely share content and/or grant access to virtual(e.g., digital content) and/or physical (e.g., buildings) resources. Forexample, UE 902 ₁ can encrypt content using the key and can broadcast(e.g., via a WiFi network, cellular network, ZigBee network, etc.) theencrypted content. Moreover, only the paired UEs 902 ₂-902 _(N) will beable to decrypt the content. As an example, a different device (notshown) in the vicinity may be able to hear the broadcast messages butwill not be able to decrypt the content since it cannot generate thesame key. In an aspect, the UE 902 ₁ can also store the encryptedcontent on a shared storage device (e.g., in the cloud) and only thepaired UEs 902 ₂-902 _(N) can retrieve and decrypt the content. As anexample, the key can be utilized during the meeting (or other event)and/or for a duration after the meeting (e.g., to share minutes or themeeting, follow-up documents, photos or videos participants recordedduring a sporting event or concert, etc.).

In one example, the key can be utilized to grant access to a physicalresource such as a restricted area. If the user of UE 902 ₁ requests toauthorize the other users of UEs 902 ₂-902 _(N) to access his home, theUE 902 ₁ can securely transmit the key to the user's home system (e.g.,a home security system that controls a lock on the house door) and/orinstruct the home system to allow the other users (that provide the samekey) to enter the house. Accordingly, when the other users arrive at thehouse, they can communicate with the home system and utilize the keys tofacilitate authentication to unlock the door. This eliminates the need(mitigates the risk involved) for the homeowner to type the key on allthe other UEs 902 ₂-902 _(N), which can be a tedious task as the numberof other UEs increases. The key can be deleted from the home system, forexample, via UE 902 ₁, via an interface (e.g., graphical user interface)on the home system, and/or via most any authorized device.

FIGS. 10-12B illustrate flow diagrams and/or methods in accordance withthe disclosed subject matter. For simplicity of explanation, the flowdiagrams and/or methods are depicted and described as a series of acts.It is to be understood and appreciated that the various embodiments arenot limited by the acts illustrated and/or by the order of acts, forexample acts can occur in various orders and/or concurrently, and withother acts not presented and described herein. Furthermore, not allillustrated acts may be required to implement the flow diagrams and/ormethods in accordance with the disclosed subject matter. In addition,those skilled in the art will understand and appreciate that the methodscould alternatively be represented as a series of interrelated statesvia a state diagram or events. Additionally, it should be furtherappreciated that the methods disclosed hereinafter and throughout thisspecification are capable of being stored on an article of manufactureto facilitate transporting and transferring such methods to computers.The term article of manufacture, as used herein, is intended toencompass a computer program accessible from any computer-readabledevice or computer-readable storage/communications media.

Referring now to FIG. 10, illustrated is an example method 1000 thatfacilitates pairing of a set of devices based on common context data,according to an aspect of the subject disclosure. As an example, method1000 can be implemented by two or more communication devices to deter,impede and/or prevent access of data or physical resources byunauthorized entities (non-paired devices). For large groups ofcommunication devices (e.g., three or more communication devices),sequential one-to-one pairing of devices within the group can be a longand tedious process. In contrast, method 1000 provides a fast andefficient approach to facilitate simultaneous (or substantiallysimultaneous) group pairing (e.g., one-to-many or many-to-many pairing)for the multiple communication devices.

At 1002, common context data can be sensed. Typically, the commoncontext data can be most any data that can be observed by a group ofcommunication devices that are close to each other (e.g., within aspecified distance from each other) and that cannot be accuratelyobserved by other devices that are further away (e.g., beyond thespecified distance). As an example, the common context data can comprisea continuous signal (e.g., motion signals, audio signals, video signals,etc.) that can change over time and that is typically not easy toreplicate at a later time. In another example, the common context datacan comprise static data (e.g., that does not change over time), suchas, but not limited to photos. The sensors that capture the commoncontext data can include, but are not limited to, an accelerometer, agyroscope, a camera, a microphone, a light sensor, a humidity sensor, atemperature sensor, a location sensor, and the like.

At 1004, a key can be generated based on the sensed data. For example,common context data collected by one or more sensors can be fused andseveral features/properties can be extracted from the common contextdata. Moreover, the features/properties can be employed to generate aseed (e.g., a sequence of bits), which in turn can be utilized togenerate the key. In one aspect, at 1006, the key can be utilized tofacilitate secure content transfer between the two or more communicationdevices. Since the same key is generated by the two or morecommunication devices, the key can be utilized to encrypt/decrypt thecontent that is transferred. In another aspect, at 1008, the key can beutilized to authorize the two or more communication devices to accessdigital content, for example, stored in a network device (e.g., cloudserver). In yet another aspect, the key can be utilized to authorize thetwo or more communication devices to access a physical resource, forexample, a room, a house, a locker, etc. As an example, a firstauthorized device of the two or more communication devices can transmitthe key to a control system that manages access to the digital contentand/or physical resource, such that the control system can authorize thepaired communication devices to access the digital content and/orphysical resource in response to receiving the key from the paireddevices.

FIG. 11 illustrates an example method 1100 that facilitates generationof a cryptographic key for pairing a group of communication devices,according to an aspect of the subject disclosure. As an example, method1100 can be implemented by two or more communication devices tofacilitate group-wise pairing. Typically, sensors of the two or morecommunication devices can monitor and/or record a continuous signal fora defined time period. At 1102, a first time at which to start sensing asignal can be determined. In one aspect, the start time can bedynamically determined by the devices, determined based oninitialization data received (e.g., from a user, service provider,device manufacturer, etc.) prior to the pairing, and/or determined basedon synchronization data received (e.g., from one or more of the devices)prior to, or during, the pairing. At 1104, signal sensing can beinitiated at the first time. At 1106, a second time at which to stopsensing the signal can be determined. In one aspect, the stop time canbe dynamically determined by the devices, determined based oninitialization data received (e.g., from a user, service provider,device manufacturer, etc.) prior to the pairing, and/or determined basedon synchronization data received (e.g., from one or more of the devices)prior to, or during, the pairing. At 1108, signal sensing can be stoppedat the second time.

At 1110, the sensed signal can be analyzed. For example, signals sensedby multiple sensors can be aggregated to determine a seed. At 1112, acryptographic key can be determined based on the analysis. For example,properties/features (e.g., size information, an aspect ratio, number ofcolors used, pixel color distribution across the image, and propertiesdetermined based on Eigenvalue-based features, SIFT descriptors, Harrisdescriptors, MOPS descriptors extracted from the sensed signals, etc.).Moreover, the key can be utilized to encrypt/decrypt content tofacilitate secure transmissions. Additionally or alternatively, the keycan be utilized as credentials to access virtual and/or physicalresources. Further, at 1114, key synchronization can be performed toverify that all the paired devices have generated identical keys. Forexample, test data and checksum values can be encrypted by utilizingcandidate keys that are generated by employing different subsets of abit sequence generated based on the sensed signal and transmitted to thepaired devices. If all the devices can accurately decrypt the test databased on a specific candidate key, the specific candidate key can beselected for encryption/decryption of subsequent content transfer.

Referring now to FIGS. 12A-12B, there illustrated are example methods(1200, 1250) that facilitate secure content transfer between two (ormore) devices, according to an aspect of the subject disclosure. In oneaspect, method 1200 can be implemented by a first device that transmitsthe content, while method 1250 can be implemented by a second devicethat receives the content. At 1202, common context data can be sensed.Typically, the common context data can be most any data that can beobserved by a group of communication devices that are close to eachother (e.g., within a specified distance from each other) and thatcannot be accurately observed by other devices that are further away(e.g., beyond the specified distance). As an example, the common contextdata can comprise, but is not limited to, motion signals, audio signals,video signals, humidity/temperature data, image data, etc. At 1204, akey can be generated based on the sensed data. For example, one or morefeatures/properties can be extracted from the common context datacollected by one or more sensors to determine a set of sequences thatcan be aggregated and/or fused to generate a seed (e.g., a sequence ofbits), which in turn can be utilized to generate the key.

At 1206, the key can be utilized to encrypt content, for example, byemploying most any encryption algorithm (e.g., hash functions, RSAalgorithm, AES, etc.). Further, at 1208, the encrypted content can bebroadcasted, for example, via a public (or private) communicationnetwork (e.g., a wireless or wired local area network (LAN), a WiFinetwork, a cellular network, a Zigbee network, etc.).

Referring now to FIG. 12B, method 1250 can be employed by the seconddevice to receive the decrypted content. In one aspect, at 1252, commoncontext data can be sensed. As an example, the second device can sensethe common context data at the same time as (or substantially the sametime as) the first device (at 1202). Further, at 1254, a key can begenerated based on the sensed data. At 1256, the encrypted content canbe received, for example, via the public (or private) communicationnetwork. At 1258, the key can be utilized to decrypt the encryptedcontent. As an example, the decrypted content can be stored within thesecond device and/or rendered on an output interface of the seconddevice.

Referring now to FIG. 13, there is illustrated a block diagram of a UE1300 that can be paired with one or more other UEs based on commonlysensed data in accordance with the subject specification. In addition,the UE 1300 can be substantially similar to and include functionalityassociated with UEs 102 a-102 f described herein. In one aspect, the UE1300 can include a processor 1302 for controlling all onboard operationsand processes. A memory 1304 can interface to the processor 1302 forstorage of data (e.g., including keys, content, and/or initializationdata) and one or more applications 1306 being executed by the processor1302. A communications component 1308 can interface to the processor1302 to facilitate wired/wireless communication with external systems(e.g., communication network 412, cloud devices 502, communicationnetwork #1 (606), communication network #2 (608), and/or communicationnetwork 708, etc.). The communications component 1308 interfaces to alocation component 1309 (e.g., GPS transceiver) that can facilitatelocation detection of the UE 1300.

The UE 1300 can include a display 1310 for displaying received content(and/or content to be transferred) and/or for displaying textinformation related to operating and using the device features. A serialI/O interface 1312 is provided in communication with the processor 1302to facilitate serial communication (e.g., USB, and/or IEEE 1394) via ahardwire connection. Audio capabilities are provided with an audio I/Ocomponent 1314, which can include a speaker for the output of audiosignals related to, for example, recorded data or telephony voice data,and a microphone for inputting voice signals for recording and/ortelephone conversations.

Further, the UE 1300 can include a slot interface 1316 for accommodatinga subscriber identity module (SIM) 1318. Firmware 1320 is also providedto store and provide to the processor 1302 startup and operational data.The UE 1300 can also include an image capture component 1322 such as acamera and/or a video decoder 1324 for decoding encoded multimediacontent. Further, the UE 1300 can include a power source 1326 in theform of batteries, which power source 1326 interfaces to an externalpower system or charging equipment via a power I/O component 1328. Inaddition, the UE 1300 can include sensors 104, key generation component106, synchronization component 202, content transfer component 204,fusion component 304, and initialization component 702, which can bestored in memory 1304 and/or implemented by an application 1306, caninclude respective functionality, as more fully described herein, forexample, with regard to systems 100-800.

Referring now to FIG. 14, there is illustrated a block diagram of acomputer 1402 operable to execute the disclosed communicationarchitecture. In order to provide additional context for various aspectsof the disclosed subject matter, FIG. 14 and the following discussionare intended to provide a brief, general description of a suitablecomputing environment 1400 in which the various aspects of thespecification can be implemented. While the specification has beendescribed above in the general context of computer-executableinstructions that can run on one or more computers, those skilled in theart will recognize that the specification also can be implemented incombination with other program modules and/or as a combination ofhardware and software.

Generally, program modules include routines, programs, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Moreover, those skilled in the art will appreciatethat the inventive methods can be practiced with other computer systemconfigurations, including single-processor or multiprocessor computersystems, minicomputers, mainframe computers, as well as personalcomputers, hand-held computing devices, microprocessor-based orprogrammable consumer electronics, and the like, each of which can beoperatively coupled to one or more associated devices.

The illustrated aspects of the specification can also be practiced indistributed computing environments where certain tasks are performed byremote processing devices that are linked through a communicationsnetwork. In a distributed computing environment, program modules can belocated in both local and remote memory storage devices.

Computing devices typically include a variety of media, which caninclude computer-readable storage media and/or communications media,which two terms are used herein differently from one another as follows.Computer-readable storage media can be any available storage media thatcan be accessed by the computer and includes both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structureddata, or unstructured data. Computer-readable storage media can include,but are not limited to, RAM, ROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disk (DVD) or other optical diskstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or other tangible and/or non-transitorymedia which can be used to store desired information. Computer-readablestorage media can be accessed by one or more local or remote computingdevices, e.g., via access requests, queries or other data retrievalprotocols, for a variety of operations with respect to the informationstored by the medium.

Communications media typically embody computer-readable instructions,data structures, program modules or other structured or unstructureddata in a data signal such as a modulated data signal, e.g., a carrierwave or other transport mechanism, and includes any information deliveryor transport media. The term “modulated data signal” or signals refersto a signal that has one or more of its characteristics set or changedin such a manner as to encode information in one or more signals. By wayof example, and not limitation, communication media include wired media,such as a wired network or direct-wired connection, and wireless mediasuch as acoustic, RF, infrared and other wireless media.

With reference again to FIG. 14, the example environment 1400 forimplementing various aspects of the specification includes a computer1402, the computer 1402 including a processing unit 1404, a systemmemory 1406 and a system bus 1408. As an example, the component(s),server(s), equipment, and/or device(s) (e.g., key generation component106, synchronization component 202, content transfer component 204,fusion component 304, initialization component 702, AI component 802,UEs 102 a-102 f, cloud devices 502, access control component 602, OTAserver 706, etc.) disclosed herein with respect to system 100-800 caneach include at least a portion of the computer 1402. The system bus1408 couples system components including, but not limited to, the systemmemory 1406 to the processing unit 1404. The processing unit 1404 can beany of various commercially available processors. Dual microprocessorsand other multi-processor architectures can also be employed as theprocessing unit 1404.

The system bus 1408 can be any of several types of bus structure thatcan further interconnect to a memory bus (with or without a memorycontroller), a peripheral bus, and a local bus using any of a variety ofcommercially available bus architectures. The system memory 1406includes read-only memory (ROM) 1410 and random access memory (RAM)1412. A basic input/output system (BIOS) is stored in a non-volatilememory 1410 such as ROM, EPROM, EEPROM, which BIOS contains the basicroutines that help to transfer information between elements within thecomputer 1402, such as during startup. The RAM 1412 can also include ahigh-speed RAM such as static RAM for caching data.

The computer 1402 further includes an internal hard disk drive (HDD)1414, which internal hard disk drive 1414 can also be configured forexternal use in a suitable chassis (not shown), a magnetic floppy diskdrive (FDD) 1416, (e.g., to read from or write to a removable diskette1418) and an optical disk drive 1420, (e.g., reading a CD-ROM disk 1422or, to read from or write to other high capacity optical media such asthe DVD). The hard disk drive 1414, magnetic disk drive 1416 and opticaldisk drive 1420 can be connected to the system bus 1408 by a hard diskdrive interface 1424, a magnetic disk drive interface 1426 and anoptical drive interface 1428, respectively. The interface 1424 forexternal drive implementations includes at least one or both ofUniversal Serial Bus (USB) and IEEE 1394 interface technologies. Otherexternal drive connection technologies are within contemplation of thesubject disclosure.

The drives and their associated computer-readable storage media providenonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For the computer 1402, the drives andstorage media accommodate the storage of any data in a suitable digitalformat. Although the description of computer-readable storage mediaabove refers to a HDD, a removable magnetic diskette, and a removableoptical media such as a CD or DVD, it should be appreciated by thoseskilled in the art that other types of storage media which are readableby a computer, such as zip drives, magnetic cassettes, flash memorycards, cartridges, and the like, can also be used in the exampleoperating environment, and further, that any such storage media cancontain computer-executable instructions for performing the methods ofthe specification.

A number of program modules can be stored in the drives and RAM 1412,including an operating system 1430, one or more application programs1432, other program modules 1434 and program data 1436. All or portionsof the operating system, applications, modules, and/or data can also becached in the RAM 1412. It is appreciated that the specification can beimplemented with various commercially available operating systems orcombinations of operating systems.

A user can enter commands and information into the computer 1402 throughone or more wired/wireless input devices, e.g., a keyboard 1438 and/or apointing device, such as a mouse 1440 or a touchscreen or touchpad (notillustrated, but which may be integrated into UE 102 in someembodiments). These and other input devices are often connected to theprocessing unit 1404 through an input device interface 1442 that iscoupled to the system bus 1408, but can be connected by otherinterfaces, such as a parallel port, an IEEE 1394 serial port, a gameport, a USB port, an IR interface, etc. A monitor 1444 or other type ofdisplay device is also connected to the system bus 1408 via aninterface, such as a video adapter 1446.

The computer 1402 can operate in a networked environment using logicalconnections via wired and/or wireless communications to one or moreremote computers, such as a remote computer(s) 1448. The remotecomputer(s) 1448 can be a workstation, a server computer, a router, apersonal computer, portable computer, microprocessor-based entertainmentappliance, a peer device or other common network node, and typicallyincludes many or all of the elements described relative to the computer1402, although, for purposes of brevity, only a memory/storage device1450 is illustrated. The logical connections depicted includewired/wireless connectivity to a local area network (LAN) 1452 and/orlarger networks, e.g., a wide area network (WAN) 1454. Such LAN and WANnetworking environments are commonplace in offices and companies, andfacilitate enterprise-wide computer networks, such as intranets, all ofwhich can connect to a global communications network, e.g., theInternet.

When used in a LAN networking environment, the computer 1402 isconnected to the local network 1452 through a wired and/or wirelesscommunication network interface or adapter 1456. The adapter 1456 canfacilitate wired or wireless communication to the LAN 1452, which canalso include a wireless access point disposed thereon for communicatingwith the wireless adapter 1456.

When used in a WAN networking environment, the computer 1402 can includea modem 1458, or is connected to a communications server on the WAN1454, or has other means for establishing communications over the WAN1454, such as by way of the Internet. The modem 1458, which can beinternal or external and a wired or wireless device, is connected to thesystem bus 1408 via the serial port interface 1442. In a networkedenvironment, program modules depicted relative to the computer 1402, orportions thereof, can be stored in the remote memory/storage device1450. It will be appreciated that the network connections shown areexample and other means of establishing a communications link betweenthe computers can be used.

The computer 1402 is operable to communicate with any wireless devicesor entities operatively disposed in wireless communication, e.g.,desktop and/or portable computer, server, communications satellite, etc.This includes at least Wi-Fi and Bluetooth™ wireless technologies. Thus,the communication can be a predefined structure as with a conventionalnetwork or simply an ad hoc communication between at least two devices.

Wi-Fi, or Wireless Fidelity, allows connection to the Internet from acouch at home, a bed in a hotel room, or a conference room at work,without wires. Wi-Fi is a wireless technology similar to that used in acell phone that enables such devices, e.g., computers, to send andreceive data indoors and out; anywhere within the range of a basestation. Wi-Fi networks use radio technologies called IEEE 802.11 (a, b,g, n, etc.) to provide secure, reliable, fast wireless connectivity. AWi-Fi network can be used to connect computers to each other, to theInternet, and to wired networks (which use IEEE 802.3 or Ethernet).Wi-Fi networks operate in the unlicensed 2.4 and 5 GHz radio bands, atan 11 Mbps (802.11a) or 54 Mbps (802.11b) data rate, for example, orwith products that contain both bands (dual band), so the networks canprovide real-world performance similar to the basic 10BaseT wiredEthernet networks used in many offices.

Referring now to FIG. 15, there is illustrated a schematic block diagramof a computing environment 1500 in accordance with the subjectspecification. The system 1500 includes one or more client(s) 1502. Theclient(s) 1502 can be hardware and/or software (e.g., threads,processes, computing devices).

The system 1500 also includes one or more server(s) 1504. The server(s)1504 can also be hardware and/or software (e.g., threads, processes,computing devices). The servers 1504 can house threads to performtransformations by employing the specification, for example. Onepossible communication between a client 1502 and a server 1504 can be inthe form of a data packet adapted to be transmitted between two or morecomputer processes. The data packet may include a cookie and/orassociated contextual information, for example. The system 1500 includesa communication framework 1506 (e.g., a global communication networksuch as the Internet) that can be employed to facilitate communicationsbetween the client(s) 1502 and the server(s) 1504.

Communications can be facilitated via a wired (including optical fiber)and/or wireless technology. The client(s) 1502 are operatively connectedto one or more client data store(s) 1508 that can be employed to storeinformation local to the client(s) 1502 (e.g., cookie(s) and/orassociated contextual information). Similarly, the server(s) 1504 areoperatively connected to one or more server data store(s) 1510 that canbe employed to store information local to the servers 1504.

As it employed in the subject specification, the term “processor” canrefer to substantially any computing processing unit or devicecomprising, but not limited to comprising, single-core processors;single-processors with software multithread execution capability;multi-core processors; multi-core processors with software multithreadexecution capability; multi-core processors with hardware multithreadtechnology; parallel platforms; and parallel platforms with distributedshared memory. Additionally, a processor can refer to an integratedcircuit, an application specific integrated circuit (ASIC), a digitalsignal processor (DSP), a field programmable gate array (FPGA), aprogrammable logic controller (PLC), a complex programmable logic device(CPLD), a discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. Processors can exploit nano-scale architectures suchas, but not limited to, molecular and quantum-dot based transistors,switches and gates, in order to optimize space usage or enhanceperformance of user equipment. A processor may also be implemented as acombination of computing processing units.

In the subject specification, terms such as “data store,” data storage,”“database,” “cache,” and substantially any other information storagecomponent relevant to operation and functionality of a component, referto “memory components,” or entities embodied in a “memory” or componentscomprising the memory. It will be appreciated that the memorycomponents, or computer-readable storage media, described herein can beeither volatile memory or nonvolatile memory, or can include bothvolatile and nonvolatile memory. By way of illustration, and notlimitation, nonvolatile memory can include read only memory (ROM),programmable ROM (PROM), electrically programmable ROM (EPROM),electrically erasable ROM (EEPROM), or flash memory. Volatile memory caninclude random access memory (RAM), which acts as external cache memory.By way of illustration and not limitation, RAM is available in manyforms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronousDRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM(ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).Additionally, the disclosed memory components of systems or methodsherein are intended to comprise, without being limited to comprising,these and any other suitable types of memory.

What has been described above includes examples of the presentspecification. It is, of course, not possible to describe everyconceivable combination of components or methods for purposes ofdescribing the present specification, but one of ordinary skill in theart may recognize that many further combinations and permutations of thepresent specification are possible. Accordingly, the presentspecification is intended to embrace all such alterations, modificationsand variations that fall within the spirit and scope of the appendedclaims. Furthermore, to the extent that the term “includes” is used ineither the detailed description or the claims, such term is intended tobe inclusive in a manner similar to the term “comprising” as“comprising” is interpreted when employed as a transitional word in aclaim.

What is claimed is:
 1. A first device, comprising: a processor; and amemory that stores executable instructions that, when executed by theprocessor, facilitate performance of operations, comprising: sensingcontext signals associated with an environment shared by the firstdevice, a second device, and a third device for a sampling period,wherein the context signals are concurrently sensed by the first device,the second device, and the third device for the sampling period, andwherein the first device and the second device are determined to belocated within a defined distance from each other; determining firstcryptographic key data based on the context signals using a defined keyfunction; receiving test data comprising first test data from the seconddevice and second test data from the third device encrypted using secondcryptographic key data determined by the second device and the thirddevice based on the context signals and using the defined key function;and verifying that the first cryptographic key data corresponds to thesecond cryptographic key data based on an ability to decrypt the testdata using the first cryptographic key data.
 2. The first device ofclaim 1, wherein the operations further comprise: encrypting contentdata using the first cryptographic key data based on the verifying, andsubsequent to the encrypting, facilitating a transfer of the contentdata to the second device and the third device, wherein the content datais capable of being decrypted by the second device and the third deviceusing the second cryptographic key data.
 3. The first device of claim 1,wherein the context signals comprise two or more signals selected from:a vibration signal applied by an external force to a surface shared bythe first device, the second device, and the third device, a soundsignal occurring in the environment, an image signal occurring in theenvironment, a temperature signal occurring in the environment, and alight signal occurring in the environment.
 4. The first device of claim3, wherein the determining the first cryptographic key comprises:selecting features from the context signals based on a common sensingmodality supported by the first device, the second device and the thirddevice, and generating the first cryptographic key based on thefeatures.
 5. The first device of claim 1, wherein the sensing thecontext signals comprises: initiating the sensing in response todetecting an initiating signal, wherein the initiating signal comprisesa defined audio signal corresponding to a start signal; and stopping thesensing in response to passage of a defined period of time.
 6. The firstdevice of claim 1, wherein the context signals comprise vibrationsignals applied to a surface upon which the first device, the seconddevice and the third device are placed, and wherein the sensing thecontext signals comprises: initiating sensing the vibration signals inresponse to detecting an initiation signal, wherein the initiationsignal comprises a defined vibration pattern corresponding to a startpattern; and stopping the sensing the vibration signals in response topassage of a defined period of time over which the vibration signals arenot detected.
 7. The first device of claim 1, wherein the contextsignals comprise vibration signals applied to a surface on which thefirst device, the second device and the third device are positioned, andwherein the determining the first cryptographic key data comprises:determining pattern information based on durations of time between thevibration signals; and determining the first cryptographic key databased on the pattern information.
 8. A method, comprising: detecting, bya first device comprising a processor, context signals from anenvironment shared by the first device, a second device and a thirddevice for a detection period, wherein the context signals areconcurrently detected by the first device, the second device and thethird device over the detection period, and wherein the first device,the second device and the third device are determined to be locatedwithin a defined distance from each other; determining, by the firstdevice, first public cryptographic key data and first privatecryptographic key data based on the context signals using a defined keyfunction; receiving, by the first device, second public cryptographickey data from the second device and the third device, wherein the secondpublic cryptographic key data was determined by the second device andthe third device based on the context signals and using the defined keyfunction; and verifying, by the first device, that the first privatecryptographic key data corresponds to second private cryptographic keydata based on correspondence between the first public cryptographic keydata and the second public cryptographic key data, wherein the secondprivate cryptographic key data was data determined by the second deviceand the third device based on the context signals using the defined keyfunction.
 9. The method of claim 8, further comprising: emitting, by thefirst device, a synchronization signal; and initiating, by the firstdevice, the detecting the context signals in response to the emittingthe synchronization signal, wherein the context signals are concurrentlydetected by the second and third device based on the emitting of thesynchronization signal by the first device.
 10. The method of claim 8,further comprising: encrypting, by the first device, content data usingthe first private cryptographic key data based on the verifying; andsubsequent to the encrypting, facilitating, by the first device, atransfer of the content data to the second device and the third device,wherein the content data is capable of being decrypted by the seconddevice and the third device using the second private cryptographic keydata.
 11. The method of claim 8, wherein the detecting the contextsignals comprises: initiating, by the first device, the detecting of thecontext signals in response to detecting a synchronization signal,wherein the synchronization signal comprises a defined vibration patterncorresponding to a start pattern, and wherein the context signals areconcurrently detected by the second device and the third device inresponse to detection of the synchronization signal by the second deviceand the third device; and stopping, by the first device, the detectingin response to passage of a defined period of time.
 12. The method ofclaim 8, wherein the context signals comprise vibration signals appliedto a surface with which the first device, the second device and thethird device are in contact, and wherein the detecting the contextsignals comprises: initiating detecting the vibration signals inresponse to detecting an initiation signal, wherein the initiationsignal comprises a defined vibration pattern corresponding to a startpattern; and stopping the detecting the vibration signals in response topassage of a defined period of time after which the vibration signalshave not been detected.
 13. The method of claim 8, wherein the contextsignals comprise vibration signals applied to a surface upon which thefirst device, the second device and the third device are placed, andwherein the determining the first cryptographic key data comprises:determining pattern information based on durations of time between thevibration signals and determining the first private cryptographic keydata and the first public cryptographic key data based on the patterninformation.
 14. A machine-readable storage medium, comprisingexecutable instructions that, when executed by a processor of a firstdevice, facilitate performance of operations, comprising: synchronizingthe first device with a second device and a third device to senseconcurrently, during a sampling period, vibration signals applied to asurface on which the first device, the second device and the thirddevice are placed, by a force external to the first device, the seconddevice and the third device, wherein the first device, the second deviceand the third device are determined to be located within a defineddistance from each other; determining first key data based on thevibration signals using a defined key function; receiving test datacomprising first test data from the second device and second test datafrom the third device encrypted using second key data determined by thesecond device and the third device based on the sequence of vibrationsignals and usage of the defined key function; and verifying that thefirst key data corresponds to the second key data based on an ability todecrypt the test data using the first key data.
 15. The machine-readablestorage medium of claim 14, wherein the operations further comprise:based on the verifying, employing the first key data to encrypt non-testdata transmitted by the first device to the second device and the thirddevice.
 16. The machine-readable storage medium of claim 14, wherein thesurface is detached from the first device, the second device and thethird device.
 17. The machine-readable storage medium of claim 14,wherein the synchronizing comprises: initiating sensing the vibrationsignals in response to detecting a synchronization signal, wherein thesynchronization signal comprises a defined vibration patterncorresponding to a start pattern, and wherein the vibration signals areconcurrently sensed by the second device and the third device inresponse to detection of the synchronization signal by the second deviceand the third device; and stopping the detecting the vibration signalsin response to passage of a defined period of time during which thevibration signals are not detected.
 18. The machine-readable storagemedium of claim 17, wherein the defined vibration pattern is responsiveto a sequence of knocks applied to the surface.
 19. The machine-readablestorage medium of claim 14, wherein the synchronizing further comprises:displaying image data on a display of the first device, and wherein thevibration signals are concurrently sensed by the first device, thesecond device and the third device based on the displaying the imagedata.
 20. The machine-readable storage medium of claim 14, wherein theoperations further comprise: based on the verifying, providing the firstkey data to an access control device that control access to a physicaldevice; and granting the access control device authority to allow thesecond device and the third device access to the physical device basedon provision of the second key data by the second device and the thirddevice to the access control device.